The present invention relates to a digital key telephone system provided in a company or an office.
A digital key telephone system comprises a main unit connected to a public network or a private branch exchange and a plurality of digital key telephones connected to the extension lines of the main unit. The digital key telephone has a plurality of push button type keys. When these keys are depressed, calling the public network or the private branch exchange, answering a call, and speech communication between digital key telephones are allowed. The main unit processes not only a control signal but also a speech communication signal as a digital signal and executes calling processing/call reception processing of each digital key telephone by a stored program control scheme and switching processing by a time switch of the digital speech communication signal.
As one of analog communication networks provided in U.S.A. recently, there is a communication network for providing a service called, e.g., xe2x80x9cCLASS (Custom Local Area Signaling Service)xe2x80x9d. The communication network for providing the CLASS service can superpose calling line identification information on a call signal and transmit it to the called subscriber.
When the digital key telephone system is connected to such a communication network, the main unit of the called digital key telephone system detects the first bell signal and then a modem signal. When calling line identification information is detected from the modem signal, the calling line identification information is transferred from the main unit to the called key telephone and displayed on the liquid crystal display device (LCD) of the key telephone. The user of the key telephone can recognize the calling line before off-hook by checking the calling line identification information displayed on the liquid crystal display device.
Conventionally, however, as the main function of the digital key telephone system using the calling line information notification service in the analog communication network such as the CLASS service, only the above-described calling line identification information display function is realized. Therefore, a demand has arisen for realization of a new and effective functional service using the CLASS service.
Another demand has arisen for expansion or realization of various support functions associated with wiring installation, a function of allowing a variety of call reception processing by adding a plurality of extension numbers to the digital key telephones, and a function of allowing a variety of communication processing operations using a personal computer combined with the digital key telephones.
It is an object of the present invention to provide a digital key telephone system capable of expanding or realizing various functions, e.g., realizing a more effective function using a calling line information notification service in an analog communication network.
In order to achieve the above object, according to the present invention, there is provided a digital key telephone system connected, through an office line, to an analog communication network having a function of transmitting a ringing signal including calling line identification information, accommodating a plurality of extension lines connected to extension terminals, and having a function of switching and connecting the office line to the plurality of extension lines or the extension lines to each other, comprising called party storage means storing information representing a correlation between a calling line and a called extension terminal in advance. By detecting the calling line identification information included in the ringing signal arriving from the analog communication network, the called extension terminal is determined on the basis of the detected calling line identification information and the information stored in the storage means, and call reception processing for the extension terminal is performed.
When called parties are registered in advance in correspondence with calling parties, an optimum extension terminal user can answer a call from a calling line. For example, a terminal for receiving and answering a call can be can be appropriately selected such that a person in charge directly answers a call from an important client, and a secretary answers calls from other clients.
In the present invention, when call reception processing is performed for the called extension terminal in response to arrival of the ringing signal, and the extension terminal does not answer the call, the calling line identification information detected from the ringing signal is stored in correspondence with the called extension terminal. When an operation of requesting call back is performed in the extension terminal which does not answer the call, call back processing is performed for the calling line on the basis of the stored calling line identification information. The calling line identification information is stored upon detecting restoration of the called office line during call reception processing.
If a call is received in the absence of the extension terminal user, the user can perform call back without the dialing operation only by performing the call back request operation. For this reason, the user operation associated with the call back operation can be simplified.
In the present invention, fault determination means using the calling line identification information is arranged. A detection result obtained when the calling line identification information included in the ringing signal is detected by the calling line identification information detection means is compared with that obtained when the calling line identification information is passed through the calling line identification information detection means together with the redundant data and detected by the fault determination means. With this operation, when a reception fault of the ringing signal is generated, determination processing is separately performed for each of the office line and the digital key telephone system.
With this arrangement, the fault occurrence position can be determined using the calling line identification information arriving from the analog communication network. As a result, separate fault determination can be relatively easily and properly performed, so a measure against the fault can be appropriately and quickly taken.
According to the present invention, there is also provided a digital key telephone system comprising an external communication interface with a plurality of serial communication ports for performing serial communication with external computer devices, and having a function of receiving function setting information sent from the external computer device through the external communication interface and setting a function of the digital key telephone system in accordance with the received function setting information, comprising function setting regulation means. While the function setting information is being received from an arbitrary one of the plurality of external computer devices, message information representing that function setting is disabled is transmitted to another external computer device, which is going to perform the function setting operation, and displayed, thereby regulating the function setting operation in another external computer device.
With this arrangement, the plurality of external computer devices are prevented from simultaneously performing function setting, so congestion of function setting processing from the plurality of external computer devices can be prevented.
When functions with different contents are set by the plurality of external computer devices, a function set by one of the external computer devices is preferentially operated in accordance with a predetermined rule. With this arrangement, even when a plurality of functions with inconsistent functions are set, the system can be prevented from erroneously operating.
In the present invention, the external communication interface comprises serial communication interface means for serially transmitting a digital signal to the external computer device, modem communication interface means for performing modem communication of a digital signal to the external computer device, and a switching circuit for switching between the serial communication interface means and the modem communication interface means. A communication request input before signal transmission to the external computer device is detected, and the switching circuit is controlled in accordance with the detection result to allow signal transmission to the external computer device as the other party of communication.
With this arrangement, data can be transmitted/ received even to/from an external computer device connected to a serial communication interface such as an RS232C or an external computer device connected through a communication line such as an office line or extension line.
In the present invention, evaluation test control means for performing an evaluation test of the digital key telephone system in cooperation with the external computer device is arranged. In addition, the external communication interface comprises a first signal path for transmitting a signal sent from the external computer device, transferring the signal to the evaluation test control means, and transferring the signal looped back by the evaluation test control means to the external computer device, and a second signal path for looping back the signal sent from the external computer device to the external computer device without transferring the signal to the evaluation test control means. The first and second signal paths are switched by the text control means.
With this arrangement, text data returned through the first signal path and that returned through the second signal path are compared in the external computer device, thereby confirming whether the control circuit in the digital key telephone system properly operates.
According to the present invention, there is also provided a digital key telephone system having an external communication interface with a plurality of serial communication ports connected to external computer devices, wherein the external communication interface comprises a table memory which stores, in advance, information representing a relationship between the number of serial communication ports connected to external computer devices and transmission rates which can be set for each serial communication port. Every time an external computer device is connected to one of the plurality of serial communication ports, a transmission rate is assigned to the serial communication port on the basis of the information stored in the table memory such that a sum of transmission rates of the plurality of serial communication ports is not more than a predetermined total transmission capability.
In accordance with the number of external computer devices connected to the serial communication ports, the maximum transmission rate can always be assigned to each external computer device within the range under the condition at that time. Therefore, data transmission can always be performed by using the transmission capacity of the external communication interface at maximum, so a high transmission capacity utilization efficiency can be maintained.
In the present invention, in mounting units or connecting extension terminals, the power factor of each of the mounted units and connected extension terminals is detected, it is determined whether the sum value of the detected power factors of the units and extension terminals falls within a prescribed value, and the determination result is notified to a user. As the determination result notification means, when the sum value of the power factors of, e.g., extension terminals exceeds the prescribed value, a warning is issued to the extension terminal to be connected.
With this arrangement, even when the installer or the like is to erroneously connect a number of extension terminals beyond the prescribed power factor value, the installer is warned of it, so connection of a number of extension terminals beyond the prescribed power factor value can be prevented.
According to the present invention, there is also provided a digital key telephone system comprising a basic cabinet accommodating a control unit for switching/connection, and a plurality of extension cabinets accommodating a plurality of interface units each having an interface function to an office line and extension lines, the extension cabinets being stacked on the basic cabinet and connected to each other through a connection cable, wherein each extension cabinet comprises stacking position recognition means for recognizing a stacking position of a self frame on the basis of a predetermined signal sent from the basic cabinet. In accordance with the stacking position recognized by the stacking position recognition means, channel conversion between an interframe transmission channel for performing signal transmission to the basic cabinet and an intraframe transmission channel for performing signal transmission to each interface unit in the self frame is performed.
With this arrangement, transmission channel conversion processing is performed in accordance with the stacking position of each extension cabinet. That is, each extension cabinet can autonomously switch the channel at any stacking position. Since the extension cabinets can have a common arrangement, manufacturing of extension cabinets can be simplified, and the cost can be reduced by the mass production effect, as compared to the manufacture of a dedicated extension cabinet at each stacking position.
In the present invention, digital level conversion means for converting an input signal level of each time slot into a different signal level and outputting the signal to a time switch for switching and connecting the office line, the extension lines, and a tone generator, and level control means are arranged. In sending a tone signal from the tone generator to the office line or the plurality of extension lines, the gain of the digital level conversion means is changed in accordance with the state of the office line or extension line to which the signal is to be sent.
As a result, even when the tone signal is to be sent to a plurality of parties, the tone signal generated by one tone signal generator can be changed in level and sent in accordance with the destination. Since a plurality of tone signal generators for generating tone signals of different levels need not be arranged, the cost of the system can be reduced, and the reliability can be improved.
In the present invention, when the system has a camp-on function of, if a new call arrives at an extension line which is communicating, sending a camp-on tone from the main unit to the extension line which is communicating to notify the call reception, the camp-on tone is changed depending on whether the line at which the call arrives is the office line or the extension line.
When another call addressed to the extension terminal during communication is received, the user of the called extension terminal can identify the calling line, i.e., the office line or extension line, from the difference in camp-on tone, so the user can appropriately answer the call in accordance with the calling line.
As means for outputting the camp-on tone from the terminal, first means for a digital key telephone and second means for a standard telephone are selectively used. When the called terminal is a digital key telephone, the main unit sends a command for instructing generation of a camp-on tone and the type of the camp-on tone because the digital key telephone has a sound source for generating the tone. Upon receiving the command, the digital key telephone generates a camp-on tone of the designated type from the sound source and outputs the camp-on tone. To the contrary, when the called terminal is a standard telephone, the main unit generates the camp-on tone by itself because the standard telephone has no tone source. The camp-on tone is mixed or inserted into the reception signal and sent to the standard telephone.
With this arrangement, the camp-on tone can be generated independently of the terminal, i.e., the digital key telephone or the standard telephone.
In the present invention, when a directory number is assigned to each extension terminal, and a directory number retrieval operation is performed in the extension terminal in a predetermined procedure, the directory number assigned to the extension terminal is read out from directory storage means and transmitted to the extension terminal which has performed the directory number retrieval operation to display the directory number.
With this arrangement, even when the user does not know or forgets the directory number of the self extension terminal, the directory number can be easily confirmed, as needed.
According to the present invention, there is also provided a digital key telephone system comprising a main unit connected to a communication network through an office line, accommodating a plurality of extension lines, and having at least a function of switching and connecting the office line to the plurality of extension lines or the extension lines to each other, and a plurality of extension terminals connected to the plurality of extension lines of the main unit, wherein when a request for knowing the contents of an incoming call is sent from one of the plurality of extension terminals, where the incoming call waiting for call reception processing is present, the main unit supplies call reception information representing the contents of the incoming call waiting for call reception processing to the extension terminal of the request source in accordance with the request.
With this arrangement, when a plurality of incoming calls are simultaneously addressed to the self extension terminal, the user can confirm the contents of these incoming calls and answer the calls in the descending order of degrees of importance. When a new incoming call is received during speech communication, the contents of the incoming call are confirmed while continuing speech communication. If the user determines that the new call is more important, the call during speech communication is held or ended. The user can immediately answer the important incoming call.
As a specific arrangement for realizing the call reception information notification function, a request for knowing the contents of the incoming call is sent from the digital key telephone, and the call reception information sent from the main unit is displayed on the digital key telephone. Alternatively, a computer device is connected to the digital key telephone through an interface. A request for knowing the contents of the incoming call is sent from the computer device, and the call reception information sent from the main unit is displayed on the computer device.
As means for sending the request for knowing the contents of the incoming call addressed to the self terminal, the request is transmitted every time a request operation is performed by a user, or the request is automatically transmitted at a predetermined timing.
When a plurality of incoming calls are addressed to one extension terminal, and every time a request for knowing contents of an incoming call is sent from the extension terminal, call reception information of one of the plurality of incoming calls is sequentially selected and supplied. Alternatively, pieces of information of all of the plurality of incoming calls may be supplied in response to one request.
According to the present invention, there is also provided a digital key telephone system comprising call park control means for, when a call park request is input in an extension terminal which is communicating, holding a call to the extension terminal in correspondence with an orbit number, and in this state, when another extension terminal accesses the orbit number, connecting the extension terminal to the held call, wherein the call park control means holds the orbit number until the call is ended in holding the call subjected to call park in correspondence with the orbit number, and when a repark request for the call is generated while the call is continuously received, the call is held in correspondence with the orbit number at which the call is being held.
With this arrangement, when a repark request is generated, the call to be subjected to call park at this time is held in correspondence with the same orbit number as that in the preceding call park. For this reason, a call is prevented from being held in correspondence with different orbit numbers.
According to the present invention, there is also provided a digital key telephone system having a computer connection interface in at least one of extension terminals wherein an operation mode change request sent from a computer is transferred to a main unit through the computer connection interface, the main unit determines whether the transferred mode change request is appropriate and supplies the determination result to the computer connection interface which has transferred to the mode change request, and the computer connection interface comprises performs mode change processing in response to the mode change request from the computer on the basis of the supplied determination result.
With this arrangement, when a mode change request is issued from the computer, the main unit always determines whether the request is appropriate. Only when it is determined that the request is appropriate, the computer connection interface performs mode change setting. Therefore, the computer connection interface can prevented from being set in a mode which is not prepared in the main unit.
For example, assume that the user sends a request for changing the mode to a computer telephoni mode from the computer to the computer connection interface to send a call using the computer. If the main unit does not have the computer telephoni mode, the main unit returns no mode change enable notification. For this reason, the computer telephoni mode is not set for the computer connection interface. Even for an appropriate mode change request, when the operation state in the main unit cannot currently cope with the mode change, the main unit returns no mode change enable notification.
According to the present invention, there is also provided a digital key telephone system having a plurality of line selection keys, in an extension terminal, each of which corresponds to the office line or extension line, wherein when the office line or the extension line corresponding to one of the plurality of line selection key is held, and in this state, a request for displaying information associated with the held office line or extension line is input in an extension terminal, the information associated with the held office line or extension line is selectively displayed on the extension terminal in accordance with the display request, and synchronized with the display operation, information representing the line selection key corresponding to the held office line or extension line is displayed.
As the means for displaying the information representing the line selection key, an indication lamp such as an LED provided in correspondence with the line selection key is turned on, or the number of the line selection key is displayed on a display device such as an LCD in correspondence with the number of the held line.
Display control of the information representing the held line and the information representing the line selection key can be performed by the main unit or the extension terminal device.
With this arrangement, the information associated with the held office line or extension line and the information representing the line selection key corresponding to the office line or extension line are displayed in correspondence with each other. For this reason, the user can always properly recognize the line selection key corresponding to the held line.
This arrangement is especially effective when a plurality of directory numbers are added to one extension terminal. When a plurality of lines with different directory numbers are being held, the user performs the display operation to, e.g., scroll the pieces of information of the held lines. Unless the user memorizes the correspondence between the pieces of displayed line information and the line selection keys, the user cannot know it. However, in the present invention, in synchronization with the scroll operation, the information of a line selection key corresponding to the displayed line is displayed, and the user can properly know the correspondence between the displayed line information and the line selection key.